How to remove and clean the Lambda sensor of a Peugeot 208

Let's see how to proceed with the removal and cleaning of the Lambda sensors on a Peugeot 208: these are located upstream of the catalytic converter and are accessible from the engine compartment, while another one is located downstream, after the catalytic converter, and is accessible from under the car. We spray some WD-40 on the threads of both sensors and let it sit for a few minutes, then we disconnect the electrical connectors and remove the sensors with a socket wrench.

We then clean them with gasoline, as shown in the video: first, we spray them with a carburetor or EGR cleaner to remove the surface dirt, then we immerse the sensitive part of the sensor in a container with gasoline (keeping the wires and connectors out!). We let it soak for at least 8 hours, then remove it, let the gasoline evaporate, and dry it completely.

Alternatively, it is possible to use a specific spray for lambda sensors (we can find it on Amazon with the code B00WEU0NO2 for the price of 17.39 euros, with free delivery), which avoids the need to use gasoline, which is highly flammable. We reassemble by hand-screwing the sensors into their respective housings, then tighten with a torque wrench to 40/60 Nm, reconnect the electrical connectors, and snap them back into their seats.